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30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
33 #include "opt_ipsec.h"
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/errno.h>
39 #include <sys/kernel.h>
40 #include <sys/malloc.h>
42 #include <sys/protosw.h>
43 #include <sys/socket.h>
44 #include <sys/socketvar.h>
45 #include <sys/sysctl.h>
48 #include <net/if_var.h>
49 #include <net/route.h>
52 #include <netinet/in.h>
53 #include <netinet/in_systm.h>
54 #include <netinet/in_var.h>
55 #include <netinet/ip.h>
56 #include <netinet/in_pcb.h>
57 #include <netinet/ip_var.h>
58 #include <netinet/ip_options.h>
59 #include <netinet/ip_ipsec.h>
61 #include <netinet/sctp_crc32.h>
64 #include <machine/in_cksum.h>
67 #include <netipsec/ipsec.h>
68 #include <netipsec/xform.h>
69 #include <netipsec/key.h>
72 extern struct protosw inetsw[];
75 #ifdef IPSEC_FILTERTUNNEL
76 static VNET_DEFINE(int, ip4_ipsec_filtertunnel) = 1;
78 static VNET_DEFINE(int, ip4_ipsec_filtertunnel) = 0;
80 #define V_ip4_ipsec_filtertunnel VNET(ip4_ipsec_filtertunnel)
82 SYSCTL_DECL(_net_inet_ipsec);
83 SYSCTL_VNET_INT(_net_inet_ipsec, OID_AUTO, filtertunnel,
84 CTLFLAG_RW, &VNET_NAME(ip4_ipsec_filtertunnel), 0,
85 "If set filter packets from an IPsec tunnel.");
89 * Check if we have to jump over firewall processing for this packet.
90 * Called from ip_input().
91 * 1 = jump over firewall, 0 = packet goes through firewall.
94 ip_ipsec_filtertunnel(struct mbuf *m)
99 * Bypass packet filtering for packets previously handled by IPsec.
101 if (!V_ip4_ipsec_filtertunnel &&
102 m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
109 * Check if this packet has an active SA and needs to be dropped instead
111 * Called from ip_input().
112 * 1 = drop packet, 0 = forward packet.
115 ip_ipsec_fwd(struct mbuf *m)
119 struct tdb_ident *tdbi;
120 struct secpolicy *sp;
123 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
125 tdbi = (struct tdb_ident *)(mtag + 1);
126 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
128 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
129 IP_FORWARDING, &error);
131 if (sp == NULL) { /* NB: can happen if error */
132 /*XXX error stat???*/
133 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/
138 * Check security policy against packet attributes.
140 error = ipsec_in_reject(sp, m);
143 IPSTAT_INC(ips_cantforward);
151 * Check if protocol type doesn't have a further header and do IPSEC
152 * decryption or reject right now. Protocols with further headers get
153 * their IPSEC treatment within the protocol specific processing.
154 * Called from ip_input().
155 * 1 = drop packet, 0 = continue processing packet.
158 ip_ipsec_input(struct mbuf *m)
161 struct ip *ip = mtod(m, struct ip *);
163 struct tdb_ident *tdbi;
164 struct secpolicy *sp;
167 * enforce IPsec policy checking if we are seeing last header.
168 * note that we do not visit this with protocols with pcb layer
169 * code - like udp/tcp/raw ip.
171 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) {
173 * Check if the packet has already had IPsec processing
174 * done. If so, then just pass it along. This tag gets
175 * set during AH, ESP, etc. input handling, before the
176 * packet is returned to the ip input queue for delivery.
178 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
180 tdbi = (struct tdb_ident *)(mtag + 1);
181 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
183 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
184 IP_FORWARDING, &error);
188 * Check security policy against packet attributes.
190 error = ipsec_in_reject(sp, m);
193 /* XXX error stat??? */
195 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
206 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
207 * Called from ip_forward().
208 * Returns MTU suggestion for ICMP needfrag reply.
211 ip_ipsec_mtu(struct mbuf *m, int mtu)
214 * If the packet is routed over IPsec tunnel, tell the
215 * originator the tunnel MTU.
216 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
219 struct secpolicy *sp = NULL;
223 sp = ipsec_getpolicybyaddr(m,
228 /* count IPsec header size */
229 ipsechdr = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL);
232 * find the correct route for outer IPv4
233 * header, compute tunnel MTU.
235 if (sp->req != NULL &&
236 sp->req->sav != NULL &&
237 sp->req->sav->sah != NULL) {
238 ro = &sp->req->sav->sah->route_cache.sa_route;
239 if (ro->ro_rt && ro->ro_rt->rt_ifp) {
240 mtu = ro->ro_rt->rt_mtu ? ro->ro_rt->rt_mtu :
241 ro->ro_rt->rt_ifp->if_mtu;
252 * Called from ip_output().
253 * 1 = drop packet, 0 = continue processing packet,
254 * -1 = packet was reinjected and stop processing packet
257 ip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error)
260 struct secpolicy *sp = NULL;
261 struct tdb_ident *tdbi;
264 * Check the security policy (SP) for the packet and, if
265 * required, do IPsec-related processing. There are two
266 * cases here; the first time a packet is sent through
267 * it will be untagged and handled by ipsec4_checkpolicy.
268 * If the packet is resubmitted to ip_output (e.g. after
269 * AH, ESP, etc. processing), there will be a tag to bypass
270 * the lookup and related policy checking.
272 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
274 tdbi = (struct tdb_ident *)(mtag + 1);
275 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
277 *error = -EINVAL; /* force silent drop */
278 m_tag_delete(*m, mtag);
280 sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
284 * There are four return cases:
285 * sp != NULL apply IPsec policy
286 * sp == NULL, error == 0 no IPsec handling needed
287 * sp == NULL, error == -EINVAL discard packet w/o error
288 * sp == NULL, error != 0 discard packet, report error
291 /* Loop detection, check if ipsec processing already done */
292 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
293 for (mtag = m_tag_first(*m); mtag != NULL;
294 mtag = m_tag_next(*m, mtag)) {
295 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
297 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
298 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
301 * Check if policy has an SA associated with it.
302 * This can happen when an SP has yet to acquire
303 * an SA; e.g. on first reference. If it occurs,
304 * then we let ipsec4_process_packet do its thing.
306 if (sp->req->sav == NULL)
308 tdbi = (struct tdb_ident *)(mtag + 1);
309 if (tdbi->spi == sp->req->sav->spi &&
310 tdbi->proto == sp->req->sav->sah->saidx.proto &&
311 bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
312 sizeof (union sockaddr_union)) == 0) {
314 * No IPsec processing is needed, free
317 * NB: null pointer to avoid free at
320 KEY_FREESP(&sp), sp = NULL;
326 * Do delayed checksums now because we send before
327 * this is done in the normal processing path.
329 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
330 in_delayed_cksum(*m);
331 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
334 if ((*m)->m_pkthdr.csum_flags & CSUM_SCTP) {
335 struct ip *ip = mtod(*m, struct ip *);
337 sctp_delayed_cksum(*m, (uint32_t)(ip->ip_hl << 2));
338 (*m)->m_pkthdr.csum_flags &= ~CSUM_SCTP;
342 /* NB: callee frees mbuf */
343 *error = ipsec4_process_packet(*m, sp->req, *flags, 0);
344 if (*error == EJUSTRETURN) {
346 * We had a SP with a level of 'use' and no SA. We
347 * will just continue to process the packet without
348 * IPsec processing and return without error.
354 * Preserve KAME behaviour: ENOENT can be returned
355 * when an SA acquire is in progress. Don't propagate
356 * this to user-level; it confuses applications.
358 * XXX this will go away when the SADB is redone.
360 if (*error == ENOENT)
363 } else { /* sp == NULL */
367 * Hack: -EINVAL is used to signal that a packet
368 * should be silently discarded. This is typically
369 * because we asked key management for an SA and
370 * it was delayed (e.g. kicked up to IKE).
372 if (*error == -EINVAL)
376 /* No IPsec processing for this packet. */